Red spots on roof of mouth, back of tongue, and throat. Arch is pastly white, painful to swallow, when cough throat hurts. Need relief asap.

To doc. This could be strep throat which it is CRUCIAL to treat. Go to a doc today and get seen. If a rapid strep test is done and negative, make sure you ask them to do a culture. Rapid tests can have false negatives 10-30% of the time and a Culture should be done to be sure you don't have it. Feel better soon! The kindest docs will swab with both swabs at once, and send the culture only if rapid neg.
Thrush? Red spots on roof of mouth, tongue and throat along with a pasty white soft palate could be Candida(thrush) if by "pasty white" you are referring to an exudate(covering) that can be scraped off. In any event, you need to have it looked at and treated by a physician.